美国人类遗传学年会：Y染色体缺失或增加老年男性个体患癌及死亡风险

  近日，在2014年美国圣地亚哥人类遗传学年会上，来自瑞典乌普萨拉大学的研究人员表示，血细胞中和年龄相关的Y染色体的缺失在老年男性中频发，而且其和老年个体多种癌症及早期死亡风险升高直接相关；这项研究为或可帮助解释为何相比女性而言，男性的寿命较短及患非性别特异性癌症的风险较高。
  大约50年前研究人员发现，Y染色体的缺失通常会在男性血细胞复制过程中偶然发生，而且其在机体全身的发生并不一致，但是研究人员并不能给出合理解释，近日就有研究人员利用血液检测技术进行了证实，研究者观察到了男性血细胞中的一小部分正在发生Y染色体的缺失。
  研究者Forsberg及其同事对70岁至84岁的1153名男性个体的血液样本进行了分析研究发现，相比血细胞Y染色体未缺失的个体而言，Y染色体缺失的个体平均存活的时间会减少5.5年；另外经历Y染色体缺失会增加个体患癌症死亡的风险。Jan Dumanski博士表示，许多人都认为，Y染色体仅仅含有和性别分化及精子产生的基因信息，实际上这些基因也具有其它的功能，比如抑制肿瘤发生等，而当Y染色体缺失发生时，Y染色体上的基因就不会进行表达，紧接着其肿瘤抑制效应也会大打折扣。
  更有意思的是，血细胞中Y染色体的缺失和许多种癌症发生相关，包括血液系统外部的很多癌症，这或许是因为Y染色体基因可以使得血细胞去帮助机体进行免疫监督，而该过程则可以帮助免疫系统鉴别并且杀灭肿瘤细胞抑制癌症发生。研究者表示，我们假设Y染色体缺失可以干扰正常的免疫监督，从而使得肿瘤细胞躲避免疫监视进而发展成为癌症。
  这项研究对于开发针对男性的新型癌症检测手段非常关键，也就是一种用于评估Y染色体缺失状况的血液检测手段；未来研究人员还会进一步详细揭示Y染色体缺失的机制，为开发针对男性的更有效的防癌手段提供一定的帮助和希望。（转化医学网360zhyx.com）
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Age-related loss of the Y chromosome (LOY) from blood cells, a frequent occurrence among elderly men, is associated with elevated risk of various cancers and earlier death, according to research presented at the American Society of Human Genetics (ASHG) 2014 Annual Meeting in San Diego.
This finding could help explain why men tend to have a shorter life span and higher rates of sex-unspecific cancers than women, who do not have a Y chromosome, said Lars Forsberg, PhD, lead author of the study and a geneticist at Uppsala University in Sweden.
LOY, which occurs occasionally as a given man's blood cells replicate – and thus takes place inconsistently throughout the body – was first reported nearly 50 years ago and remains largely unexplained in both its causes and effects. Recent advances in genetic technology have allowed researchers to use a blood test to detect when only a small fraction of a man's blood cells have undergone LOY.
Dr. Forsberg and colleagues studied blood samples from 1,153 elderly men aged 70 to 84 years, who were followed clinically for up to 40 years. They found that men whose samples showed LOY in a significant fraction of their blood cells lived an average of 5.5 years less than men whose blood was not affected by LOY. In addition, having undergone LOY significantly increased the men's risk of dying from cancer during the course of the study. These associations remained statistically significant when results were adjusted for men's age and other health conditions.....